He may have been the most terrifying carnivore ever to have walked the Earth but the fearsome Tyrannosaurus rex was apparently also a sensitive lover.

Experts say the 20ft T-rex had an extremely sensitive snout, which could mean that males and females enjoyed rubbing their faces together while mating.

Writing in the Scientific Reports journal, US researchers wrote: "In courtship, tyrannosaurids might have rubbed their sensitive faces together as a vital part of pre-copulatory play."

It comes following the discovery of an earlier relative of the T-rex - the Daspletosaurus horneri (Horner's frightful lizard), which lived 74 million years ago - in the US state of Montana.

Scientists were able to examine several well-preserved fossil skulls and skeletons, and said the face of the D-horneri gave the most important clues about the Tyrannosaurus anatomy.

Image:The T-rex had teeth that could rip prey apart

It is believed that T-rex had large, flat scales on its face, with areas of tough protective skin around the snout and jaws.

But the hard surface around the nose was penetrated by small nerve openings, which would have allowed hundreds of branches of the trigeminal nerve - responsible for sensation in the face - to run through to the surface of the dinosaur's nose.

This would effectively have turned the T-rex's face into a kind of third "hand", as sensitive to touch as a human finger tip.

Other animals also have this sensitivity nerve - cats through their whiskers and crocodiles in their snouts to sense touch and vibrations in the water. Migrating birds also use it to detect magnetic fields.

Scientists said the T-rex may well have used it to explore its environment and to pick up fragile eggs, but it was possible it also provided an enjoyable sensation when mating.

Professor Jayc Sedlmayr, from Louisiana State University, said: "Our finding of a complex sensory web is especially interesting because it is derived from the trigeminal nerve, which has an extraordinary evolutionary history of developing into wildly different 'sixth senses' in different vertebrates."